996
FXUS64 KJAN 111726
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1226 PM CDT Sun Aug 11 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 830 AM CDT Sun Aug 11 2024

No changes needed this update with a fantastic day in store so
enjoy it while you can because heat will be making a return this
week. Very dry conditions are observed this morning with dewpoints
in the low to mid 60s, leading to very comfortable conditions. A
decaying complex is visible on satellite over Oklahoma and should
not maintain into our area, but could bring in some clouds in the
northwestern portions. Fire danger is a concern today in light of
the dry conditions and will continue to message limited risk in
HWO./SAS/

&&

.DISCUSSION...
Issued at 305 AM CDT Sun Aug 11 2024

Today and tonight: Temps have dipped into the mid and upper 60s
across most of the area overnight. Another seasonably warm and
comfortable day is on tap as a relatively dry airmass remains
across the region. Decent vertical mixing and some continued dry
advection are again expected as we warm up, allowing dewpoints to
potentially dip into the 50s in some areas by midday and the early
afternoon. The only real weather feature of peripheral interest
is a convective complex currently over OK. As this progresses
further eastward through the day and into this evening, it is
expected to diminish as it encounters greater subsidence within
the low level ridge axis. For tonight, with the drier airmass,
temps will readily dip into the 60s and lower 70s once again.

There is still rather limited concern for fire danger today. Fuel
moisture is decreasing but largely remains around seasonal norms
for the time being (this could change in coming days with more
heat and continued lack of rainfall). Meteorologically, daytime
RHs could tease critical thresholds but winds will mainly be
light. All in all, increasing caution should be exercised with
fires, but this is still quite a marginal threat for now. /DL/

Monday through the weekend...

Overall forecast for the long term period remains the same with
no major adjustments made. The primary focus for this portion of
the long term forecast will be the return of dangerous heat
conditions along with high temperatures and associated heat
advisories/warnings starting on Monday/Tuesday. Dry conditions
will continue Wednesday through Friday as future global guidance
highlights a sfc high migrating out of the Southern Plains and
merging with a subtropical ridge extending from the Gulf of
Mexico.

Monday through Wednesday

Quiet weather conditions will continue to dominate our forecast
heading into Monday as a 594dm high will dominate our forecast
area and continue to push drier air across the southeast region.
This will allow for a dry sfc front to linger through the southern
portions of our forecast area with some low end PoP chances
(between 12-16%) mainly for areas along and south of the Hwy 84
corridor by early Monday afternoon. With afternoon highs peaking
in the mid to upper 90s and dewpoints climbing back into the low
to mid 60s, heat indices will hover between 100-105F degrees.
Similar conditions will occur on Tuesday as dry conditions persist
north of I-20 corridor. Afternoon highs will peak into the mid to
upper 90s around this timeframe, with a few areas east of I-55
reaching the low 100s. This, combined with dewpoints climbing into
the low 70s, will yield heat indices in the 105-110F deg range.
If heat trends continue to increase heading into Tuesday, we will
likely introduce a heat graphic in our HWO for this timeframe and
will continue advertise this graphic heading into the mid week.
Likewise, a Heat Advisory is likely for our entire forecast area
for Tuesday including portions of southeast Arkansas and all of
our northeast Louisiana parishes.

Hot and humid Gulf flow will make a return to the forecast region
by mid day Wednesday as the aforementioned sfc front lingering
across the southern portions of central MS tracks southeast
towards the Gulf Coast. This will unfortunately cause temperatures
associated with this flow to see a return to our uncomfortable/
sweltering summertime temperatures/heat indices with several areas
south of I- 20 climbing above 110F deg. A Heat Advisory will
likely be needed heading into Wednesday. There is some
discrepancies with model consensus in regards to the precise
orientation of this pattern, which in turn, allow for some
uncertainty in low PoPs and rain chances for Wednesday afternoon.
At the moment, we are looking at chance for scattered showers and
storms east of I-55 with low end PoP chances hovering in the
15-25% range.

Thursday through Sunday

Thursday will see a continuation of hot conditions with areas
east of I-55 seeing afternoon temperatures climb in the low 100s
with the rest of the area seeing highs in the upper 90s. Heat
indices will be similar to Wednesday with isolated areas south of
I-20 and across the Delta seeing heat indices above 110F. Heat
trends will begin to decrease Friday/Saturday as future guidance
hints at continued weakening and reorientation of the 700mb ridge
axis. This will allow for mid-level cloud coverage that spills
over into the region which could help lower our afternoon highs
heading into the weekend. If this scenario comes to fruition, we
could see an overall reduction in in heat indices of 3-5F. This
decrease should be just enough to help us fall below below heat
advisory/warning criteria. With that being said, areas along and
east of I-55 will have a slight chance (around 15-30%) for
scattered showers and storms.

Heading into Sunday, future guidance highlights a building ridge
axis across the Northern Plains. At the same time, a positively
tilted trough axis will continue its southward propagation towards
the southeast CONUS. As this trough axis continues to dig
southward, southwesterly moisture flow from the Gulf will help
support afternoon scattered showers and t-storms, with the
greatest coverage of low PoP chances (around 25%) east of I-55.
Although cloud coverage will start to increase slightly,
sufficient daytime heating will help afternoon highs peak in the
upper 90s, with a couple of areas reaching low 100s. With
dewpoints expected to climb in the low to mid 70s around this
timeframe, heat indices will once again be in the 105F-110F deg
range. Heat trends will continue to be monitored. /CR/

&&

.AVIATION...
(18Z TAFS)
Issued at 1223 PM CDT Sun Aug 11 2024

Quiet VFR conditions prevail with mostly clear skies. A few high
clouds will move into the northwest, particularly at site GLH and
gradually spread southeastward. Winds will prevail from the north,
northeast around 5 to 8kts./SAS/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       71  96  74  99 /   0   0   0  10
Meridian      68  96  72  99 /   0   0   0  10
Vicksburg     71  97  75  99 /   0   0   0  10
Hattiesburg   71  98  74 100 /   0   0   0  10
Natchez       72  97  74  98 /   0   0   0  10
Greenville    69  94  73  98 /  10   0   0  10
Greenwood     69  95  73  98 /   0   0   0  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

$$

DL/CR/SAS20